Part of the thrust, in Vista, Windows Defender, and for Microsoft in
the security area (Per Bill Gates' RSA speech this year) is to
simplify.
I don't think you'll see much more complexity added to the UI--the
functionality is there for those that want to dig, and the UI is
simple enough that the average user--and face it, those folks are
very different from those who find there way to these groups and are
doing beta testing, by and large)--can handle it without problems.
This is also behind some of the decisions about update mechanisms and
the lack of an easily accessable "update" button, I believe.
When you need to count the number of things you need to do to "be
safe" on more than a few fingers, life is getting too complex--I'm in
favor of the de-emphasis--I want this to be something that is just
out there on every machine, and doesn't bug me (as an admin, or the
users)--not that I can say that it has managed that so far!